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how do you typically tie the address pins and WP pin of I2C device? Do these lines need a pull-up/down resistor or just tied directly.

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closed as unclear what you're asking by uint128_t, Neil_UK, Peter Smith, Adam Haun, Daniel Grillo Mar 28 '16 at 11:11

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    \$\begingroup\$ Reading the datasheet would be a good place to start. \$\endgroup\$ – uint128_t Mar 26 '16 at 0:47
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Do these lines need a pull-up/down resistor or just tied directly.

Completely dependent on the specific IC you are using, and would be listed in the data sheet. Either outright, or in the recommended/typical application schematic.

That said, I've never personally seen one that couldn't be directly tied to VCC or Gnd. Unless it is one of the fancier ones that can be tied to voltage dividers, or the other address pins, or left floating.


Your specific part, the FM24V02 has both an explicit explanation, and a typical application schematic. Direct Connections shown.

A2-A0, Input, Device Select Address 2-0.
These pins are used to select one of up to 8 devices of the same type on the same I2C bus. To select the device, the address value on the three pins must match the corresponding bits contained in the slave address. The address pins are pulled down internally.

WP, Input, Write Protect.
When tied to VDD, addresses in the entire memory map will be write-protected. When WP is connected to ground, all addresses are write enabled. This pin is pulled down internally.

enter image description here

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  • \$\begingroup\$ Ok, nothing is mentioned in datasheet. So i can tie directly to VDD or VSS as per my requirement \$\endgroup\$ – engineer Mar 25 '16 at 22:17
  • \$\begingroup\$ @engineer what part, what data sheet \$\endgroup\$ – Passerby Mar 25 '16 at 22:18
  • \$\begingroup\$ FM24V02 F-RAM part \$\endgroup\$ – engineer Mar 25 '16 at 22:21
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    \$\begingroup\$ page 3 of the datasheet says " When tied to VDD, addresses in the entire memory map will be write-protected. When WP is connected to ground, all addresses are write enabled. This pin is pulled down internally." I think that's pretty clear. \$\endgroup\$ – The Photon Mar 25 '16 at 22:24
  • \$\begingroup\$ My question for slave address pins A0, A1, A2. Even these pins are pulled down internally, if i want to pull down externally, should i tie directly to VSS or through resistor? \$\endgroup\$ – engineer Mar 25 '16 at 22:29

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